1. Field of the Invention
The subject invention is directed to optical control mechanisms for fluid power systems and, more particularly, optical control systems that directly control a fluid power system without the requirement of intermediate electrical or fluid stages.
2. Description of the Prior Art
Fluid power systems are used in a wide range of applications to provide the controlled movement of mechanical parts. Typically, such fluid power systems have been controlled by electromagnetic control devices responsive to electrical control signals provided from control components of the system. However, the bulk and weight of such fluid power systems tended to be undesirable for many applications. Also the electrical control circuitry of such systems was subject to interference and damage so that it required shielding or protective devices that increased the cost of the system and further contributed to its bulk and weight. Also, the relative complexity of such systems tended to make them more subject to failure. Therefore, in applications where reliability, size and weight are important considerations, a simpler, smaller, lighter control system would be desirable.
Optical-type fluid power control systems that control power components of the hydraulic system by optical control signals are known in the prior art. However, such prior optical control systems do not control the hydraulic system directly with optical signals. For example, such prior optical control systems often employ a photoelectrical receiver and a remote electrical power supply in combination with a conventional electromagnetic control component. The photoelectrical receiver was powered by a remote electrical power supply that was specially designed to reject spurious interference. Because such prior optical systems required the equipment to convert the optical control signal to an electrical control signal, they actually compounded the complexity, size and weight of the fluid control system.
Accordingly, there was a need in the prior art for an optical control system that would control the hydraulic power system directly with optical control signals and that did not require conversion to intermediate control modes. Previously, it has been accepted that the power available from optical energy sources did not permit direct control of the hydraulic system with optical signals.